being \(\delta _{ij}\)  the Kronecker delta.Note that the \(T_i\)  matrices are antihermitian. But, one can easily recover an hermitian set by multiplying the matrices by \(i\) . Of course, in order to obtain the same solutions presented below we need to multiply the \(F_i\)  function also by \(i\) . The complete mathematical formulation of the above construction can be found
in Refs. [1]}, [2]} and [3]}
(see also [4]}, [5]}, [6]} and [7]} for recent applications in physics).
